The objective of the Training Program in Immunology at Sloan-Kettering Institute is to provide postdoctoral fellows a solid foundation in the field of Immunology and to direct their interests towards important aspects of the immune system and its response to infectious agents, self-antigens, and cancer. Four postdoctoral positions are requested for this competitive renewal, which is unchanged from the past grant period. Duration of training will be two years. The Training Program provides Trainees with the intensive training, resources, and experience necessary for them to develop successful careers in academia, government, and industry as independent researchers and leaders. Areas of research training cover lymphocyte development and biology, signaling, innate immunity, infectious immunity, transplantation immunity and cancer immunology. The objectives of the Training Program are achieved by providing a structured environment with i n tensive involvement in immunology research, further strengthened by attendance at weekly seminars and research-in-progress meetings and a yearly retreat, along with participation in advanced courses covering contemporary topics of immunology. The major part of the training comes from the research experience under the tutelage of preceptors who are engaged in excellent immunology research, with bearing on lymphocyte biology, cell signaling and transcription, innate immunity, infectious diseases, autoimmune diseases, transplantation and cancer. Trainees can also take advantage of the many interdisciplinary collaborations between members of the Immunology Training Program and respected outside scientists, both locally and nationally.